Heretofore it has been a common practice when fabricating and assembling containers or other products using blow molded components having thin sections to be joined together at such sections to join such components with adhesives because thin walled, blow molded components generally can't accommodate common ultrasonic weld joints. Unfortunately, as is known by those skilled in the art adhesive joining has several disadvantages. Examples of such disadvantages are, that their use releases volatile organic compounds into the atmosphere. In addition, adhesive joining typically requires the employment of fixtures or jigs to align and constrain the constituent parts during the time that the adhesive is curing. Such curing (or drying) of the adhesive can necessitate long curing or drying times depending upon the type of adhesive used. Moreover, excess adhesive must be removed post joining. Lastly, adhesively joined products may exhibit poor heat tolerance, making the products unsuitable to dishwasher cleaning or in other applications that are hot.
Some blow molded components may be bonded together using ultrasonic welding. As is known in ultrasonic welding entails mechanical vibrations of low amplitudes and high frequencies which generate cyclic deformation at the weld interface (joint). The combination of mechanical vibrations and axial force generates heat at specific weld joint geometries to enable flow and bonding to occur. Assemblies that are joined with ultrasonic welding must be robust enough or fixtured (i.e., supported with some type of fixture) since fixtures help localize the mechanical vibrations and improve the efficiency of heat generation.
Accordingly, a need exists for a method of permanently joining thin portions of blow molded components together to produce a product without the use of adhesives and to do so by use of ultrasonic welding on a expeditious and relatively low cost basis. The subject invention addresses those needs.